Locking electrical connector



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United States Patent O 3,500,291 LOCKING ELECTRICAL CONNECTOR HarveyHubbell, Southport, and Ernest R. Carlson, Fairfield, Conn, assignors toHarvey Hubbell, Incorporated, Bridgeport, Conn., a corporation ofConnecticut Filed Jan. 29, 1968, Ser. No. 701,149 Int. Cl. H01r 13/54US. Cl. 339-91 Claims ABSTRACT OF THE DISCLOSURE A rotatable electricalconnector cap having supplementary locking means in the form of aretractable locking pin normally exendable outwardly of the face of theconnector cap and having retracting means in the form of a reciprocalannular sleeve encircling the connector cap, which may be manuallygrasped to retract the locking pin, to rotate the connector cap and todraw it axially from the mating connector body.

BACKGROUND OF THE INVENTION This invention relates to a lockingelectrical connector and, more particularly, to a connector of the typewherein a separable connector cap is rotatable relative to a receptacleor a connector body and in which supplementary locking means areprovided to prevent reverse rotation and uncoupling of the connector.

Rotatably locking separable electrical connectors are well known in thewiring art. In a connector of this type, the end face of the usualreceptacle or connector body defines a plurality of arcuate slots whichare arranged about a common center and communicate with internallyformed chambers enclosing the female contacts. The separable cap portionof the connector carries a plurality of axially extending L-shapedblades which are also positioned about a common center. To mate the capand receptacle, the blades are inserted into the corresponding arcuatesloths and into the female contacts. The cap is then rotated in aclockwise direction, the blades remaining within the female contacts andthe circumferentially extending portions of the L-shaped blades becomemisaligned with the slots and extend behind the face of the receptacle.It is then impossible to separate the cap from the receptacle by adirect axial pull. To separate the two members the cap must be rotatedcounterclockwise relative to the receptacle body to realign the bladesand slots before withdrawal.

Although rotatably locking electrical connectors are widely andsuccessfully used throughout the electrical industry, it would bedesirable to provide a connector having an even more positive lockingmeans. This is particularly true where the connectors are used incertain industrial applications where they may be subjected toconsiderable vibration. It is possible under such circumstances for thecap to be vibrated counterclockwise relative to the receptacle so thatthey become unlocked from one another.

In the copending application of Harvey Hubbell, Ser. No. 515,596, filedDec. 22, 1965, now US. Patent 3,393,395 assigned to the same assignee asthe instant application, there are illustrated several embodiments oflocking mechanisms which may be incorporated in a locking electricalconnector. These embodiments each comprise a conector cap having aspring biased retractable latch pin arranged to enter a complementarylocking aperture defined in a connector body after the connectorcomponents have been rotated relative to one another.

SUMMARY OF THE INVENTION It is the primary object of this invention toprovide a rotatable locking electrical connector cap having supple-Patented Mar. 10, 1970 mentary locking means and which may be used withstandard receptacles and connector bodies.

Another object of this invention is to provide a rotatably lockingelectrical connector cap with a latch pin and latch pin retracting meansin the form of an annular sleeve which may be grasped when handling thecap. A further object is to provide a connector cap of the typedescribed which is neat in appearance, and is inexpensive tomanufacture.

To accomplish these objects, in one form we have provided a rotatablylocking electrical connector cap with retractable locking means normallyextending beyond the face of the cap positioned to enter a slot in astandard mating connector component upon rotation of the connector cap,and reciprocable annular retracting means encircling the connector capand secured thereto for manually grasping the connector cap, retractingthe locking means, rotating the connector cap and removing the connectorcap from the mating connector component.

BRIEF DESCRIPTION OF THE DRAWING Other objects and further details ofthat which we believe to be novel and our invention will be clear fromthe following description and claims taken with the accompanyingdrawings, wherein:

FIG. 1 is a side elevational view of an electrical connector cap and astandard receptacle shown in a separated condition;

FIG. 2 is a partial sectional view taken substantially along the line2-2 of FIG. 1 showing the latch pin retracting means;

FIG. 3 is a front elevational view of the receptacle shown with theblades of the connector cap inserted into the slots thereof prior tobeing rotated, the latch pin bearing on the planar end wall of thereceptacle;

FIG. 4 is a front elevational view of the receptacle similar to that ofFIG. 3, showing the blades of the connector cap in their rotatedposition with the latch pin disposed in the grounding slot of thereceptacle;

FIG. 5 is a sectional view taken substantially along line 5-5 of FIG. 2with the connector cap and receptacle in the same relationship as shownin FIG. 4; and

FIG. 6 is a sectional view similar to that of FIG. 5 showing the annularsleeve having been retracted to draw the latch pin from the receptacleslot.

DESCRIPTION OF THE PREFERRED EMBODIMENT With particular reference to thedrawing, there is illustrated a standard receptacle 10 having a mountingstrap 12- for securement to a usual wall box. It should be understoodthat, although a receptacle has been shown, a standard connector bodymay be substituted therefor throughout this description. The receptaclebody is made of a suitable plastic insulating material and includes aplanar face 14 defining a plurality of slots 16 therein, each describingan arc segment of a common circle. The slots communicate with usualinternal chambers which house suitable female contacts in a knownmanner. Binding head terminal screws 18 (only two of which are shown inFIG. 1) electrically connected to the female contacts are arranged toreceive electrical current carrying wires from a power source. As theinternal construction of the receptacle is conventional, it is notillustrated nor is it discussed in great detail.

In FIG. 1 our unique electrical connector cap 20 is shown separated fromthe receptacle 10 and aligned therewith. The embodiment of our connectorcap, as herein disclosed, shows a cap having four contact blades 22,these being two line blades, 21 neutral blade and a grounding blade.Each blade has one of its ends embedded in the insulating material ofthe connector cap, while the opposite end extends from the body and hasthe usual circumferentially extending overhanging portions 24 forlocking the connector cap 20 in the receptacle 10 upon rotation of thecap in a known manner. The grounding blade 22G extending farthest fromthe planar face 26 of the connector cap, so that it may engage thefemale grounding contact of the receptacle before the other blades,thereby protecting the system, includes a radially inwardly extendingkeying portion 28.

The body of the connector cap comprises a front insulation portion 30, acentral insulation portion 32, a rear insulation portion 34 and aprotective metal shell 36, the rear insulation portion and the metalshell being secured to the remaining portions by means of elongatedsecuring screws 38. Blades 22 pass through the front insulation portion,being embedded in the central insulation portion wherein they aresecured to usual contact terminals in a wiring area (not shown) definedbetween the central and rear insulation portions 32 and 34. The wiringarea accepts the bared ends of a load cable 40 which engage the bladecontact terminals. The load cable 40 passes through the metal shell 36and rear insulation portion 34, being held in place and strain relievedby a cable clamp 42.

The front insulation portion 30 comprises an annular disc having acentral axial Opening 44, a radially outwardly extending flange 46located at one end which is coextensive with its planar face 26,circumferentially spaced radially inwardly extending keyways 48 forminga splined cylindrical wall and a long narrow cavity 50 located betweentwo of the keyways. A post 52 extending from one face of the centralinsulation portion 32, passes into the central axial opening 44 and isheaded at 54 to secure the front insulation portion to the centralinsulation portion. It should be understood that the two portions 30 and32 may be secured together in any other desired manner.

An annular sleeve 56 made of a suitable plastic insulating material iscarried by and encircles the major portion of the connector cap 20,being axially movable relative thereto. The sleeve is formed with adouble cylindrical wall including an interior wall 58 and an exterioroutwardly flared wall 60 which define a circumferential channel 62therebetween to receive the cylindrical side wall of the metal shell 36.Interior wall 58 lies adjacent the cylindrical outer surface of theinsulation portions 30, 32 and 34. Extending radially inwardly from theinterior wall at one end thereof are plural circumferentially spaced keyportions 64 and a single tongue 66. The exterior flared wall 60 isformed with a knurled surface 68 to aid in grasping the connector cap.When the annular sleeve 56 is located upon the connector cap 20 the keyportions 64 and the tongue 66 enter the keyways 48 and the long narrowcavity 50, respectively.

A bushing 70 made of a low friction plastic material may be positionedthrough the end wall of the front insulation portion over the narrowcavity 50 and is axially aligned with an opening 72 defined in thetongue 66. Latch pin 74 having a head 76 at one end passes through boththe opening 72 and the bushing 70. A compression spring 78, disposed ina recessed seat 80 defined in the central insulation portion 32, bearsagainst the head 76 to bias the latch pin 74 leftwardly (as viewed inFIGS. and 6) urging it to protrude beyond the planar face 26 of theconnector cap 20. The compression spring 78, located off center relativeto the connector cap, adequately serves to bias the annular sleeve 56leftwardly as shown in FIGS. 1 and 5. Cocking and binding of the annularsleeve are prevented because the keying portions. 64 ride upon thesplined front insulation portion. It should be apparent that the singlecompression spring 78 performs two functions: (1) it biases the annularsleeve 56 leftwardly; and (2) it biases the latch pin 74 leftwardly toallow it to move independently of the annular sleeve,

When in use, our unique connector cap 20 is handled in a manner similarto the usual rotate-to-lock connector caps. It is necessary first toalign the blades 22 with the slots 16 of a standard receptacle 10 asillustrated in FIG. 1. It should be noted that the latch pin 74protrudes from the planar face 26 of the connector cap. Then the blades22 are inserted into the slots 16 until the planar face 26 is contiguouswith the planar face 14 wherein the latch pin 74 is caused to bedisplaced into the connector cap with its end bearing against the planarface 14 of the receptacle 10 (see FIG. 3). The connector cap may besecured to the receptacle in the usual manner by rotation thereof. Whenthe connector cap has been fully rotated, the latch pin 74 is alignedwith the end of the grounding slot 16G and is urged into the areavacated by the rotated grounding blade 22G (see FIGS. 4 and 5). Thiseffects a positive locking of the connector cap with the receptaclesince the latch pin 74 prevents counter-rotation of the connector cap.When effecting coupling as described above, the annular sleeve 56 isgrasped and is rotated in a manner similar to the handling of the usualconnector cap, the keys 64 in the keyways 48 effectively transmittingthe rotational force from the sleeve to the cap.

In order to disconnect the connector cap 20 and the receptacle 10, it isnecessary to draw back the annular sleeve 56 to withdraw the latch pin74 from the grounding slot 22G (see FIG. 6), counter-rotate theconnector cap relative to the receptacle, and then axially remove theconnector cap. It should be noted that the user may draw back theannular sleeve while simultaneously counterrotating it and the cap. Thisis possible due to our unique key and spline construction.

As set forth in the objects of the invention, we have provided a neatappearing spring-biased annular sleeve which forms an actuator devicefor retracting a latch pin. The sleeve is easily grasped and willtransmit axial, as well as rotational, forces to the cap. Our uniquelocking-type connector cap may be used with any standard receptacle orconnector body of the rotateto-lock type which has the same number ofblades.

It should be understood that the present disclosure is made only by wayof example and that numerous changes in details of construction and thecombination and arrangement of parts may be resorted to withoutdeparting from the true spirit and the scope of the invention.

What is claimed is:

1. A rotatable electrical connector cap comprising: an insulating body;a plurality of elongated contact blades secured in said body forselective insertion into and through the slots formed in a matingconnector device, said blades being of a size to be relatively rotatablein the slots; retracting sleeve means at least partiallyenclosing saidinsulating body and reciprocably axially movable relative thereto;interlocking means for substantially preventing rotation of said sleevemeans relative to said insulating body; and retractable locking meansnormally extending beyond the face of the cap and positioned to enterone of said slots upon rotation of said connector cap, said lockingmeans engaging said sleeve means for axial movement therewith.

2. The connector cap defined in claim 1 wherein said locking meanscomprises a pin reciprocably mounted in said body with one end capturedtherein and being biased outwardly of said body.

3. The connector cap defined in claim 1 wherein said sleeve means has aknurled, substantially cylindrical outer surface for assisting inmanually grasping said connector cap.

4. The connector cap defined in claim 1 wherein said interlocking meansincludes plural circumferentially spaced axially extending keywaysformed in said body and plural mating circumferentially spaced axiallyextending key portions formed on said sleeve means.

5. The connector cap defined in claim 4 wherein a spring biases saidsleeve means toward the face of the cap.

6. The connector cap defined in claim 4 wherein said locking meanscomprises a pin reciprocably mounted in said body with one end capturedtherein and a spring seated in said body to bias said pin outwardly ofsaid body and said sleeve means toward the face of the cap.

7. A rotatable electrical connector cap comprising: an insulating body;a plurality of elongated contact blades secured in said body forselective insertion into and through the slots formed in a matingconnector device, said blades being of a size to be relatively rotatablein the slots; retracting means at least partially enclosing saidinsulating body and reciprocably axially movable relative thereto;interlocking means including an axially and radially inwardly extendingrecess formed in said body, and a mating radially inwardly extendingtongue formed on said retracting means positioned to enter said recessfor substantially preventing rotation of said retracting means relativeto said insulating body; and retractable locking means normallyextending beyond the face of the cap and positioned to enter one of saidslots upon rotation of said connector cap, said locking means engagingsaid retracting means for axial movement therewith.

8. The connector cap defined in claim 7 wherein said locking meanscomprises: a pin reciprocably mounted relative to said body and saidtongue and carried by said tongue; and a spring seated in said bodybiasing said pin outwardly of said body.

9. A rotatable electrical connector cap comprising: an insulating body;a plurality of elongated contact blades secured in said body forselective insertion into and through the slots formed in a matingconnector device, said blades being of a size to be relatively rotatablein the slots; a cup-shaped protective shell having a planar end wall anda cylindrical skirt secured to the insualting body; retracting means atleast partially enclosing said insulating body and reciprocably axiallymovable relative thereto and including a sleeve defining acircumferential channel at one end positioned to receive saidcylindrical skirt; interlocking means for substantially preventingrotation of said retracting means relative to said insulating body; andretractable locking means normally extending beyond the face of the capand positioned to enter one of said slots upon rotation of saidconnector cap, said locking means engaging said retracting means foraxial movement therewith.

10. A rotatable electrical connector cap comprising: an insulating body;a plurality of elongated contact blades secured in said body forselective insertion into and through the slots formed in a matingconnector device, said blades being of a size to be relatively rotatablein the slots; retracting means including a spring biased sleeve at leastpartially enclosing said insulating body and reciproably axailly movablerelative thereto and having a knurled, substantially cylindrical outersurface for assisting in manual grasping of the connector cap;interlocking means for substantially preventing rotation of saidretracting means relative to said insulating body including pluralcircumferentially spaced axially extending keyways and an axially andradially inwardly extending recess formed in said body, and pluralmating circumferentially spaced axially extending key portions and aradially inwardly extending tongue formed on the inner surface of saidsleeve; a pin normally extending beyond the face of the cap andreciprocably mounted relative to said body and said tongue and carriedby said tongue for axial movement therewith and positioned to enter oneof said slots upon rotation of said connector cap; and a spring seatedin said body to bias said pin outwardly of said body and said sleevetoward the face of the connector cap.

References Cited UNITED STATES PATENTS 2,684,860 7/1954 Rafierty 285-2,750,571 6/1956 Schmier 339103 3,393,395 7/1958 Hubbell 33991 MARVIN A.CHAMPION, Primary Examiner I. H. MCGLYNN, Assistant Examiner s. c1. X.R,age-19s

